As the valve opening and closing timing control device having the configuration described above, a technique is disclosed in JP2009-515090T in which a valve housing is screwed and fixed to an inside of the cam shaft, a pressure medium guidance insert is disposed on an inside of the valve housing, a control piston (spool) is disposed on the inside of the valve housing so as to be movable in a direction along an axis of the cam shaft, and the control piston is operated by an external electrical adjustment unit (actuator).
In JP2009-515090T, a pair of ports communicating with a pressure chamber for controlling the relative rotational phase is formed on an inner surface of the pressure medium guidance insert and a flow path for supplying a pressure medium supplied to the valve housing to the control piston through a flow path between the inner surface of the valve housing and the pressure medium guidance insert is formed.
Furthermore, a technique is disclosed in US2012/0097122A1 in which an attachment bolt is screwed and fixed to an inside of a cam shaft, a spool is disposed on the inside thereof so as to be movable in a direction along an axis of the cam shaft, and the spool is operated by an external actuator.
In US2012/0097122A1, a pair of ports communicating with an advance angle chamber and a retarded angle chamber is formed in an inner surface of the attachment bolt, a flow path for supplying a fluid supplied to the cam shaft to the spool by allowing the fluid to pass through a part of a flow path forming member on an outer periphery of the cam shaft is formed.
As disclosed in JP2009-515090T and US2012/0097122A1, the valve opening and closing timing control device for controlling the fluid by the spool provided coaxially with the cam shaft performs supply and discharge of the fluid from a position in the vicinity of the advance angle chamber or the retarded angle chamber. Thus, it is possible to rapidly operate the valve opening and closing timing control device by suppressing operation delay caused by flow path resistance.
However, in this configuration, since the spool is disposed coaxially with the cam shaft, the fluid is supplied from an external fluid pressure pump of the cam shaft and the fluid is supplied to the spool through the flow path formed in the cam shaft.
As described above, when considering the configuration in which the flow path is formed in the cam shaft, in the technique disclosed in JP2009-515090T, since the flow path is formed by forming the pressure medium guidance insert on the inside of the valve housing, the number of components is increased and it leads to a cost increase. Furthermore, in this configuration, it is likely to lead to leakage of the fluid between the valve housing and the pressure medium guidance insert, and to lead to performance degradation due to the flow path resistance caused by a bending flow path.
In the technique disclosed in US2012/0097122A1, the flow path is formed by disposing the flow path forming member on the outer periphery of the attachment bolt. Thus, similar to JP2009-515090T, the number of components is increased, it leads to a cost increase, and it is likely to lead to leakage of the fluid, and lead to performance degradation.